Sucking pests

Introduction

A tiny aphid presses its sucking mouthparts against a plant leaf to feed. Inside the visible mouth is an even tinier, set of hypodermic needle-like mouth parts that draw sap from plant veins.

Insects that use special sucking mouth parts to feed on sap and plant cells include some of the most diverse and interesting insects in the garden. They can also be some of the most destructive pests in home landscapes. Unlike the beetles and ants with their chewing mouth parts, insects that feed on sap have piercing/sucking mouth parts. Damage from sap feeders can be difficult to spot at first. After a while, however, plants being attacked by sap-feeders will take on a shiny look and sticky feel. Eventually these sticky plants may turn black with a coating of black sooty mold, a type of fungus that grows on the sugars in the drippy droppings of sap-feeders. Common sap-feeding insects include mealybugs, scale insects, aphids, true bugs and whiteflies.

Leafhopper feeding damage to mint. The lighter-colored spots are typical of damage caused by mesophyll-feeding insects and mites.

Not all plant-feeding insects with sucking mouth parts feed on sap. Some feed on the inner tissues of leaves, called mesophyll (MEEZ oh fill). Mesophyll includes the food producing (photosynthetic) cells layers of a leaf that lie between the upper and lower epidermis. Symptoms of mesophyll feeding include a stippled pattern of yellowish, gray or whitish dots on the plant surface. This damage causes the leaf color to dullen, turn yellow or gray, and eventually brown. Other mesophyll feeders may leave pits or sunken areas of leaves that eventually turn brown and die. Spider mites, leafhoppers, lace bugs and yucca bugs are examples of mesophyll-feeders common in Texas landscapes.

Frequently Asked Questions

Sap-feeding insects

Aphids in Texas Landscapes (E-311) Aphids are among the most common sucking insect pests on Texas landscape plants. Found on leaves, stems, and even roots of plants, aphids feed on the phloem (sap) and leave behind weakened plants and sticky honeydew.

Box elder bugs (E-453) Box elder bugs feed with their piercing sucking mouthparts fmaple and box elder seeds. While this does no damage to the tree, their presence in and around the home is a concern.

Chili thrips (EEE-000412) Though not a true sap-feeding pest, these tiny insects are becoming an increasingly important and serious pest in roses.

Crape Myrtle Bark Scale Tracking The EDDMapS website allows you to report and verify new locations of this scale. If you believe you have CMBS on your crape myrtle, check out this site. You can upload your own pictures for expert verification and literally put your pest on the map. If you are outside the Dallas Fort Worth area, especially, your reports are needed.

Scale insects (B-6097) One of the more important, sap-feeding pest groups. Some scales are very difficult to find and control. This publication provides an overview of scale insects and control recommendations.

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